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Method for making electrical contact to a wafer with very thin Cu seeds or directly to a thin barrier material to enable electroplating

IP.com Disclosure Number: IPCOM000020732D
Publication Date: 2003-Dec-10
Document File: 3 page(s) / 201K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for making electrical contact to a wafer with very thin Cu seeds or directly to a thin barrier material to enable electroplating. Benefits include improved functionality, improved performance, and improved reliability.

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Method for making electrical contact to a wafer with very thin Cu seeds or directly to a thin barrier material to enable electroplating

Disclosed is a method for making electrical contact to a wafer with very thin Cu seeds or directly to a thin barrier material to enable electroplating. Benefits include improved functionality, improved performance, and improved reliability.

Background

Conventional electroplating hardware uses many pointed prongs at multiple discreet points along the circumference of a wafer to make electrical contact to Cu seed layers (see Figure 1). While this style of electrical contact is acceptable for relatively thick Cu seeds, the use of a pointed electrical contact may pierce thin Cu seeds or barrier material into to the underlying low dielectric constant (K) material (see Figure 2). This poor electrical contact results in poor electroplating current distribution, poor uniformity, and gapfill.

High clamping pressures are conventionally used in electroplating tools (approximately 25 psi). Reliability issues occur but pressures cannot be reduced due to concerns over backside contamination.

General description

         The disclosed method makes electrical contact around the complete circumference of a wafer with very thin Cu seeds to permit Cu electroplating. The method lowers the clamping pressure on a wafer in a Cu plating tool during electroplating to be more compatible with mechanically weak low-K dielectric films.

Advantages

         The disclosed method provides advantages, including:

•         Improved functionality due to primarily contacting an underlying low-K material instead of a conductive seed or barrier material

•         Improved functionality due to protecting the backside of a wafer from contamination

•         Improved functionality due to forming a seal on the frontside as well as the backside of the wafer because of a lower clamping pressure on a wafer in a Cu plating tool during electroplating

•         Improved performance due to improved electrical contact to a wafer for electropl...